It is known in the prior art to provide for movement of window and door panels by prime movers, including electric motors. Many such arrangements are unwieldy and complicated, rendering them awkward and difficult with regard to both installation and use. A search of the prior art located the following patents which are believed to be representative of the state of the prior art: U.S. Pat. No. 2,684,239, issued Jul. 20, 1954, U.S. Pat. No. 3,403,474, issued Oct. 1, 1968, U.S. Pat. No. 1,952,821, issued Mar. 27, 1934, U.S. Pat. No. 3,344,556, issued Oct. 3, 1967, U.S. Pat. No. 3,890,744, issued Jun. 24, 1975, U.S. Pat. No. 4,858,383, issued Aug. 22, 1989, U.S. Pat. No. 4,541,202, issued Sep. 17, 1985, and U.S. Pat. No. 4,893,435, issued Jan. 16, 1990.